Belt for speed-varying devices.



T. P. CHISHOLM. BELT FOR SPEED VARYING DEVICES.

APPLICATION FILED MAY I2. 1916.

11. ,23&&9%0 Patented Aug. 28, 1917.

"marten stares rimrr THOMAS P. cHIsnoLM, or saeinnw, MICHIGAN, assrenoa TO A. r. rnlannnr. & 00., or

- snenvnw, MICHIGAN, A coaronnrron or MICHIGAN.

BELT non srnnn-vnnvrne DEVICES.

Specification of Letters Patent.

Patented Aug. 28, 1913.

To all whom it may concern:

Be it known that I, THOMAS P. CHISHOLM, a citizen of the United States, residing at Saginaw, in the county of Saginaw and State of Michigan, have invented certain new and useful Improvements in Belts-for Speed-Varying Devices; and I do hereby declare the following to be afull, clear, and

exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention is a power transmission belt adapted for use in speed-varying mechanisms of the type employing two pairs of cone-shaped disks, the disks of each pair slidably mounted on a shaft and adapted to be moved toward and from each other.

Such speed-varying mechanisms are usually also provided with means whereby the disks of one pair may be moved toward or from each other while simultaneously the other pair of disks are moved away from or t0- ward each other. i

The belts used are known as V-belts and usually consist in a fiat band or its equivalent, to which blocks ofwood or like material are secured, the blocks located crosswise the belt and having their ends beveled to suit the faces of the conical disks. The ends of the blocks are usually tipped with leather, which provides the driving surface.

It is the object of my present invention to provide a belt for this class of speedvarying machines that will be simple in construction, light, yet strong and durable; easily assembled and capable of exerting a great degree of tractive effort. Y

A further object is to so construct the belt that its fiat central body (this being the part of the belt that transmits the pull of the load from one pair of cones to the other) may be formed integral with the traction tips that bear against the working faces of the disk, for purposes that will appear later in the specification.

With these and certain other objects in view which will appear later in the speoification, my invention comprises the device described and claimed, and the equivalents thereof.

In the drawings, Figure 1 is a plan view of a short length of my improved belt, flattened, the traction tips being extended to show the manner in which they are formed.

Fig. 2 is a similar view showing the tips bent into their working position.

Fig. 3 is an enlarged cross section on line 3-3 of Fig. 2.

Figs. 4 and 5 are diagrammatic views showing the relation of the ml-belt to the two sets of conical disks 011 which it runs. Fig. 6 is an enlarged side view of a part of the belt as it appears when bent.

As is clearly shown in the drawing, the V-belt consists in a single band or belt of leather or equivalent material, the band being cutto form a central strap or tension body 1, having a plurality of laterally projecting wings or tips 2.

These tips are preferably formed by making transverse slits in. the edges of the band, at suitable intervals, and providing an opening 4;, which may bemade by punching or otherwise, at the inner end of each slit. The opening 4 may be of. any suitable shape, but I prefer to make it substantially elliptical, or elongated, with curved ends, as indicated in Fig. 1. There is thus formed along the edges of the band 1 a plurality of tips 2, which, when bent nearly at right angles to the body, as shown in Fig. 3, form traction members that tightly grip the working faces of the usual cone disks 5 and 6.

Spacing blocks 7 of wood or equivalent material are secured to the body 1 between each pair of traction members or tips 2. The blocks may be secured to the body of the belt in any suitable manner, as by screws 8, and the tips may if desired be secured to the ends of the blocks by nails 9, or otherwise, although for many classes of service it may not be necessary to fasten the tips 2 to the ends of the blocks.

It will be noted that in my improved V-belt the body 1 of the belt transmits the pull of the load from one set of disks, as the driving set 5, Figs. 4: and 5, to the driven set, 6, and that this load is transmitted by reason of the tension in the fibers of the body 1, as in ordinary flat belt transmissions. But it will also be noted that the driving traction is transmitted to the body of the belt through the tips 2, which are gripped by the working faces of the disks. The entire traction is not transmitted from the tips to the body of the belt through the blocks 7 and their fastenings 9 and 8, as is the case where the tips are made separate from the belt and merely attached to the ends of the block, but, on the contrary, a considerable part of the tractive force is transmitted direct from the tips 2 to the body 1 by reason of the fact that the tips themselves are integral with the body of the belt. Thus the fastenings 8 are relieved of a large part of the work of power transmission, and the-blocks 7 are relieved of a large part of the transverse or splitting stress that would otherwise be brought upon them, and, as above noted, the fastenings 9 may in certain classes of service be entirely dispensed with.

Relieving the blocks 7 and their fastenings 8 of a strain in the manner described results in longer life of the V-belt, for there is less tendency to pull the heads of fastenings 8 through the belt, or to loosen their anchorage in the blocks 7. The blocks are less liable to split under heavy load, and

are better able to perform their main function of resisting the compressive stress which is brought upon them by the traction disks.

The V-belt, as indicated in Fig. 6, is almost as free to bend and'as flexible as if there were no tips upon its edges.

Having thus described my invention, what Copies of this patent may be obtained for transverse blocks carried bysaid band, said band having a plurality of lateral slits formed along its opposite edgesfwhereby a plurality of laterallyv extending tips are formed integral with said body, said tips bent to overlap the ends of said blocks.

3.A belt for speed-varying machines comprising a tension band or body, and

transverseblocks carried by said band, said band having a plurality of lateral slits formed along its opposite edges, said band at the inner extremity of each slit formed with an opening, whereby a plurality of laterally extending tips are formed integral with said body, said tips bent to voverlap the ends of said blocks. a

In testimony whereof I aifix my ture in presence of two witnesses.

THOMAS P. OHISHOLM.

Witnessesw E. BURKHOLDER, Gno. B. WILLGOX.

signafive cents each, by addressing the Commissioner ,of Patents,

Washington, D. G. 

